A new study presented today at the World Congress on Osteoporosis (IOF WCO-ECCEO10) in Florence, Italy shows that DMPA, a commonly used injectible contraceptive, is associated with higher risk of bone fracture when used alone, and not in combination with estrogens.
Depot medroxyprogesterone acetate (DMPA) is a progestin-only long acting reversible hormonal contraceptive birth control drug which is injected every 3 months. It is used by more than 9 million women worldwide, with high usage among teenagers in Europe and the US. Previous studies have shown that use of DMPA is associated with impaired bone acquisition during adolescence and accelerated bone loss later in life, mainly in younger women with lower estrogen levels. However, few studies have looked into the impact of DMPA on fracture risk.
The study, conducted by researchers at the University Hospital Basel, Switzerland and the Boston University Medical Center, Lexington, USA, used a case-control analysis to evaluate the relationship between long-term use of DMPA, with or without estrogen, and the risk of fractures. The results show that in women below 50 years of age, longer-term use of DMPA of two and more years is associated with a 50% increased risk of fracture. For users of combined estrogen-containing oral contraceptives fracture risk was not increased.